Food processors such as juicers or blenders are appliances frequently used in people's daily lives. Food processors typically employ a motorized cutting tool which rotates at high speed to cut the food. However, this processing manner has a potential risk. If the motor and cutting tool cannot stop in time in case a top cover is unintentionally opened during operation of the food processor, the food processor may cause damage to a user. IEC (international electrotechnical commission) safety standards require a cutter of the food processor to stop in 1.5 seconds in case of emergency such as when the top cover of the food processor is opened or moved away. Many commercial available food processors cannot satisfy the IEC safety standards. In addition, some food processors employ a special mechanism such that the top cover cannot be opened before the motor stops. However, this increases cost of the food processor.
In addition, during the emergency stopping process of the motor when the top cover of the food processor is suddenly opened, regenerated energy that is produced by continuing rotation of the motor due to inertia imposes an overvoltage risk on the motor, which may decrease a lifespan of internal components of a motor driving circuit.